The present invention relates to masa sheeting apparatus and, more particularly, to such apparatus in which a wire is employed to peel the masa sheet from the sheeting rollers.
Masa sheeting machines are used in the production of thin corn products formed from unleavened cornmeal dough such as tortillas and tortilla chips. These machines have for decades comprised a pair of sheeting rollers positioned beneath a hopper. The masa squeezed between the rolls forms a sheet which adheres to the rollers. The sheet is peeled from one of the sheeting rollers by a wire so that the entire sheet is carried by the second roller. A cutting device acting against the second roller outlines product pieces in the sheet. A second peeling wire is provided to strip the masa sheet and the product pieces from the second roller after the cutting operation. The product pieces fall onto a take-away conveyor, but the scrap portions of the sheet are carried along with the roller back into the hopper by thin hoops fitted to the roller.
The second roller is provided with spaced circumferential grooves in which the hoops are loosely positioned. The hoops are formed in place from bands having adjustably interlocking ends. The formed hoops have a diameter slightly less than that of the roller so that they remain captive within the grooves. The grooves are sufficiently deep to allow the hoops to assume eccentric positions in which they protrude from the grooves a significant distance.
As the masa sheet is formed between the sheeting rollers, the masa is pressed against the hoops as well as the cylindrical surfaces of the rollers. Therefore, the masa sheet adheres to the hoops also. The second peeling wire is threaded through the hoops so that as the wire peels the masa sheet from the surface of the roller, the sheet continues to adhere to the hoops and the cut pieces are severed from the sheet and fall onto the take-away conveyor as the sheet is peeled from the roller, but the remainder of the sheet (the scrap) is carried by the hoops back into the hopper. For the decades that this type of machinery has been in operation, piano wire or similar high tensile strength round wire has been used exclusively as the peeling wires. The preferred wire size is 0.014 inch in diameter. Wire of 0.016 inch diameter is also used, although it does not peel as well as the thinner wire. Over these decades of use, there has been a consistant pattern of breakage of the peel wires. The wires used to peel the cut masa sheet from the second sheeting rollers break after an average of about 8 hours of use. The wires used to peel the masa sheet from the first sheeting rollers break after an average of about 32 hours of use. Each machine has a double set of sheeting rollers and, therefore, on the average 21/2 wires must be replaced per machine during each eight-hour work shift. Replacement of each wire requires 15 to 20 minutes, during which time the machine is inoperative. Therefore, up to 50 minutes of an eight-hour shift is conventionally lost.
Therefore, on the average, each machine is idle for 30 to 50 minutes during each eight-hour shift with a resulting loss of up to 10% of production.